| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 32.51 | 34 |
| 2015 | 30.96 | 52 |
| 2014 | 31.73 | 52 |
| 2013 | 33.49 | 45 |
| 2012 | 35.59 | 40 |
| 2011 | 34.59 | 45 |
| 2010 | 32.29 | 54 |
| 2009 | 26.66 | 91 |
| 2008 | 28.56 | 82 |
| 2007 | 26.91 | 95 |
| 2006 | 27.73 | 91 |
| 2005 | 24.61 | 110 |
| 2004 | 20.51 | 133 |
| 2003 | 21.32 | 132 |
| 2002 | 19.48 | 134 |
| 2001 | 17.15 | 145 |
| 2000 | 16.61 | 149 |
| 1999 | 22.63 | 119 |
| 1998 | 22.5 | 117 |
| 1997 | 21.05 | 125 |
| 1996 | 21.15 | 120 |
| 1995 | 19.24 | 131 |
| 1994 | 18.14 | 115 |
| 1993 | 17.74 | 109 |
| 1992 | 17.76 | 111 |
| 1991 | 16.82 | 118 |
| 1990 | 14.51 | 120 |
| 1989 | 13.42 | 106 |